Re: [PATCH 12/31] perf probe: Reset args and nargs for probe_trace_event when failure

From: Arnaldo Carvalho de Melo
Date: Thu Oct 29 2015 - 18:39:51 EST


Em Wed, Oct 14, 2015 at 12:41:23PM +0000, Wang Nan escreveu:
> When failure occures in add_probe_trace_event(), args in
> probe_trace_event is incomplete. Since information in it may be used
> in futher, this patch frees the allocated memory and set it to NULL
> to avoid dangling pointer.

Masami, can I have your Acked-by for this one?

Thanks,

- Arnaldo

> Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
> Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx>
> Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> Cc: David Ahern <dsahern@xxxxxxxxx>
> Cc: He Kuang <hekuang@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Kaixu Xia <xiakaixu@xxxxxxxxxx>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Cc: Zefan Li <lizefan@xxxxxxxxxx>
> Cc: pi3orama@xxxxxxx
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Link: http://lkml.kernel.org/n/ebpf-6yw9eg0ej3l4jnqhinngkw86@xxxxxxxxxxxxxx
> ---
> tools/perf/util/probe-finder.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index bd8f03d..b1581d7 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -1235,6 +1235,10 @@ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
>
> end:
> free(args);
> + if (ret) {
> + tev->nargs = 0;
> + zfree(&tev->args);
> + }
> return ret;
> }
>
> --
> 1.8.3.4
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